Hot runner manifold systems are utilized to transfer molten material, typically plastic resin, from an injection molding machine to a mold. Hot runner manifold systems typically include a manifold plate, a manifold housed in the manifold plate, and a backing plate that supports the manifold and manifold plate. The manifold system routes molten material from a central sprue, which connects to an injection unit on an injection molding machine, to a plurality of nozzles which inject the molten material into cavities in the mold. The manifold system divides the flow of the molten material into several branches as it flows from the central sprue to the nozzles.
Referring to FIGS. 1 and 2, a prior art manifold system using two plates is shown with portions of the plates and main manifold cut away to reveal internal detail. A manifold assembly 10 is located between a manifold plate 12 and a backing plate 14. Sprue 16 connects to the manifold 10 at a central location. Manifold 10 has one or more melt channels 18 that communicate the molten material from the manifold 10 to nozzles (not shown) connected to the manifold 10.
One limitation of these prior art systems is that the backing plate 14 and manifold plate 12, in addition to the manifold 10, must be replaced each time a new hot runner system is desired. While the need for new manifolds and nozzles is largely unavoidable, the possibility of reusable plates represents a significant potential cost and time saving benefit. Even though the backing and manifold plates add relatively little value to a hot runner system relative to the manifolds and nozzles, these parts can represent as much as 30-40% of the cost of a new hot runner system
Therefore, it would be desirable to provide a hot runner plate system that is reusable with new or modified manifolds and nozzles.
The present invention is directed to meeting one or more of the above-stated desirable objectives.